The invention relates to fastener tools and particularly to fastener tools with pivotable nosepiece covers.
Fastener tools are used for driving nails or staples into workpieces. Referring to FIGS. 5A and 5B, it is well known in the art to provide such tools with nosepiece 31 and nosepiece cover 32 rotatably attached to nosepiece 31 via pin 31P. To lock the nosepiece cover 32 in place, prior solutions include providing hooks 31H on nosepiece 31. The latch 33 is pivotably attached to nosepiece cover 32 via pin 32P. Latch 33 may have a tab 33T for allowing the user to move the latch between the locked and unlocked positions. Latch 33 also carries a spring 34, which is typically made of wire. Typically, the spring 34 has one bend 34B between hook 31H and latch 33. Nosepiece cover 32 contacts the underside of spring 34 at the hook area.
Typically, spring 34 is inserted into latch 33 by ears 34E. Ears 34E are typically inserted into latch 33 and are typically oriented substantially perpendicular to the longitudinal axis of nosepiece 31. Such arrangement is also problematic because, over time, ears 34E bend away from the end of 31E of nosepiece 31 (shown as 34E′ in broken lines). Also, the wear on latch 33 and ears 34E is accelerated because of the high loads placed on and/or because of the relative motion of the spring 34. This contributes to a loss of force in spring 34, thus allowing the nosepiece cover 32 to open slightly during firing, and increasing the possibility of a nail jamming between nosepiece 31 and cover 32.
A prior art solution to such problem has been to add swages 34S (shown in broken lines) to ears 34E. However, this is a difficult and expensive manufacturing process which may not ultimately prevent bending.